Patent GB-849057-A (GB)
Title: Rotatable well pressure seal
IPC: E21B33/08
Filed: 1958-12-18
Abstract: 849,057. Boring earth &c. HYDRIL CO. Dec. 18, 1958 [March 10, 1958], No. 40853/58. Class 85. The entry of well fluid to a clearance space between rotary and stationary parts of a kelly packer is prevented by surrounding the entrance to the clearance space by a closure which contains a barrier liquid, e.g., a high melting point grease with a low mineral oil content, the closure including a floating piston which transmits well fluid pressure to the barrier liquid to prevent migration of the well fluid to the clearance space. Figs. 1, 3 show a kelly packer 18 and a blow-out preventer 19, the packer being withdrawn in Fig. 1, and operatively positioned in Fig. 3. The packer includes an elastic P for embracing and rotating with the kelly (not shown in Fig. 3), and the blow-out preventer which is as described in Specification 627,196, includes an elastic body S which is stationary and is contractible to seal against a stationary sleeve 201 separated from the rotating sleeve 67 which carries the body-P, by the clearance space 202 from which well fluid is excluded by the pressurized grease in the space 211. The pressure is applied to the grease by an annular piston 212 and the entrance to the clearance space is the leakage path between the working faces of a stationary ring 205 and a rotating ring 230 pressed against the ring 205 by springs 236. Rotating parts 219, 220 are clamped by taper means 224 to the sleeve 67, and an outer sleeve 210 is secured to the port 219 at 226, splines 234 on the part 219 driving the ring 230. The piston 212 is pressed upwardly by well fluid pressure. The blow-out preventer 19 comprises a piston 33 moved up or down by admission of pressure fluid at 36 or 37 whereby a conical face 40 contracts, or allows expansion of, the body S which is reinforced against axial flow by metal inserts 45 having flanges 48 which, when the body S is contracted to bear against the stationary sleeve 201 of the kelly packer, lock into a groove 63. The sleeve 67 is driven from the kelly, two split rings 148, 149 which embrace the kelly having a multiple spline connection 144 with a sleeve 145, the lower part of which is provided with tongues 141 engaging recesses 142 in the top of the sleeve 67 which is demountably threaded at 69 to a bearing sleeve 66 surrounded by ball thrust bearings. The body P comprises a metal cage consisting of top and bottom rings 111, 112 and connecting bars 113, the ring 111 having an upstanding flange 117 to fit around the sleeve 67, and a horizontal flange 118 for attachment thereto by bolts 108. The body P is moulded around the cage and the bottom part is shaped to allow the kelly to be inserted therethrough and to embrace the non- circular section under well pressure. The cage prevents the upper part from being collapsed on to the kelly and also prevents objectionable axial flow of the resilient material. In a modification, Fig. 12, the leakage path 277 into the space 261 between the rotary sleeve 67 and the stationary sleeve 260 is between the working faces of a rotary ring 267 and the lower end of the sleeve 260. The contraction of the body S tends to displace the sleeve 260 downwardly, but this is resisted by well-fluid pressure acting on the sleeve 272 which rotates with but is slidable on the sleeve 67, whereby the working faces 277 are kept tightly in contact. An annular cylinderpiston 285 which may, or may not, rotate is pressed down by well pressure to pressurize grease in the space 280. In a further modification, the cylinder-piston 285 is held against rotation, and the pressure between the working faces 277 is maintained by spring-means. In Fig. 20, the leakage path 420 into the clearance space 403 between rotary and non-rotary parts 300, 402 is between the working faces of the rotary part 300 and a stationary sleeve 405. Grease 408 is pressurized by well fluid pressure acting on the top face of a cylinder-piston 412 which is free to rotate or not to rotate. U.S.A. Specification 2,731,281 is referred to.